HYBRID SYSTEM FOR POSITION DETERMINATION BY A MOBILE COMMUNICATIONS TERMINAL

摘要

A mobile unit includes a network receiver, such as a GSM telephone, for communication with a wireless network, and a navigation receiver, such as a global positioning system (GPS) receiver for receiving navigation signals. The navigation receiver includes a vector delay lock loop (VDLL) that receives information concerning the navigation sources, such as satellite data messages, transmitted over a common broadcast channel of the wireless network, and receives navigation signals from the navigation receiver. The VDLL uses the navigation signals received from navigation sources that are not obscured and uses satellite data messages broadcast over the wireless network to track a navigation signal that is received only intermittently due, for example, to the navigation source being obscured from view of the mobile unit.